Comparing Marginal Revenue to Marginal Cost

Comparing marginal revenue to marginal cost
(i) reveals the contribution of the last unit of production to total profit.
(ii) is helpful in making profit-maximizing production decisions.
(iii) tells a firm whether its fixed costs are too high.

A) (i) only
B) (i) and (ii) only
C) (ii) and (iii) only
D) (i) and (iii) only